When Joy tells Teddy that Tanya's daughter liked his pictures, she asks him to see her in room 22. In the next scene the number on the door as Teddy enters is 25.
In the last party scene where Teddy lights April's cigarette he uses both hands in one shot, but when the angle changes only one hand is in frame holding the lighter.
When April is babysitting Michael, he is playing Mortal Kombat (2011). The buttons show on screen are the buttons on the Playstation controllers, while in the actual scene we see Michael and April playing with Xbox 360 controllers. The Xbox 360 is also the video game sitting besides the TV.
When April is babysitting, she turns on a movie for the little boy, who says he likes the film. What they're supposed to be watching is Fast Times at Ridgemont High, but the song being played is not the Cars' version of Moving in Stereo, nor is the scene played from the actual film, but a Phoebe Cates look-alike in a red bikini baring her breasts. What's shown and heard is clearly not from the film, even the background is quite obviously different.